Stent-valves for valve replacement and associated methods and systems for surgery

ABSTRACT

Stent-valves (e.g., single-stent-valves and double-stent-valves), associated methods and systems for their delivery via minimally-invasive surgery, and guide-wire compatible closure devices for sealing access orifices are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/433,910, which was filed Mar. 29, 2012 and which is adivisional of U.S. patent application Ser. No. 11/700,922, filed on Dec.21, 2006, which claims the benefit of U.S. Provisional PatentApplication Nos. 60/753,071, filed Dec. 22, 2005, 60/755,590, filed Dec.29, 2005, and 60/843,181, filed Sep. 7, 2006, each of which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

Embodiments of the present invention relate to stent-valves, associatedmethods and systems for their delivery via minimally-invasive surgery,and guide-wire compatible closure devices for sealing access orifices.

BACKGROUND OF THE INVENTION

Conventional approaches for cardiac valve replacement require thecutting of a relatively large opening in the patient's sternum(“sternotomy”) or thoracic cavity (“thoracotomy”) in order to allow thesurgeon to access the patient's heart. Additionally, these approachesrequire arrest of the patient's heart and a cardiopulmonary bypass(i.e., use of a heart-lung bypass machine to oxygenate and circulate thepatient's blood). Despite their invasiveness, these surgical approachesmay be reasonably safe for a first intervention. However, tissueadherences resulting from the first surgery may increase the risks(e.g., death) associated with subsequent valve replacement surgeries.See Akins et al., “Risk of Reoperative Valve Replacement for FailedMitral and Aortic Bioprostheses”, Ann Thorac Surg 1998; 65:1545-52; andWeerasinghe et al., “First Redo Heart Valve Replacement—A 10-YearAnalysis”, Circulation 1999; 99:655-658; each of which is incorporatedby reference herein in its entirety.

Synthetic valves and biological valves have been used for cardiac valvereplacement with varying results. Synthetic valves rarely fail butrequire life-long anti-coagulant treatment to prevent blood fromclotting (thrombosis) in and around the replacement valve. Suchanti-coagulant treatment significantly limits patients' activities andcan cause various other complications. Biological valves do not requiresuch anti-coagulation treatment but typically fail within 10-15 years.Thus, to limit the need for and risks associated with re-operation onfailed biological valves, traditionally only patients with less thanabout 10-15 years to live have received biological valve replacements.Patients with longer life expectancies have received synthetic valvesand anti-coagulant treatment.

Attempts have been made to develop less-invasive surgical methods forcardiac valve replacement. These surgical methods, referred to aspercutaneous heart valve replacement therapies (PHVT), use a catheter todeliver a replacement valve to an implantation site using the patient'svascular system. These PHVT attempts have various shortcomings,including their inability to ensure proper positioning and stability ofthe replacement valve within the patient's body.

Conventional closure devices for closing access orifices are alsolacking in several respects, including the looseness of their fit whichcan cause bleeding after surgery. These closure devices also lack acentral lumen, which renders them incompatible with guide wire deliverysystems. One such conventional closure device is described in MalgorzataPawelec-Wojtalik, “Closure of left ventricle perforation with the use ofmuscular VSD occluder”, European Journal of Cardio-Thoracic Surgery 27(2005) 714-716, which is incorporated by reference herein in itsentirety.

In view of the foregoing, it would be desirable to provide improvedmethods, systems, and devices for cardiac valve replacement.

SUMMARY OF THE INVENTION

Some embodiments of the present invention are directed to systems,methods, and devices for cardiac valve replacement. For example, thesemethods, systems, and devices may be applicable to the full range ofcardiac-valve therapies including the replacement of failed aortic,mitral, tricuspid, and pulmonary valves. In some embodiments, thepresent invention may facilitate a surgical approach whereby surgery isperformed on a beating heart without the need for an open-chest cavityand heart-lung bypass. This minimally-invasive surgical approach mayreduce the risks associated with replacing a failed native valve in thefirst instance, as well as the risks associated with secondary orsubsequent surgeries to replace failed artificial (e.g., biological orsynthetic) valves.

Stent-valves according to some embodiments of the present invention mayinclude a valve component and at least one stent component. The valvecomponent may include a biological or synthetic (e.g., mechanical) valveand/or any other suitable material(s). The stent component may include afirst section (e.g., proximal section), a second section configured tohouse the valve component, and a third section (e.g., distal section).The stent and valve components may be capable of at least twoconfigurations: a collapsed configuration (e.g., during delivery) and anexpanded configuration (e.g., after implantation).

In some embodiments, the first section of the stent valve may include afixation element. Such a fixation element may include, for example, anannular groove for securing the stent-valve in place at an implantationsite. When the stent-valve includes a single stent(“single-stent-valve”), the annular groove may be configured to receivethe annulus of the valve in need of replacement. When the stent-valveincludes two stents (“double-stent-valve”), the annular groove of thefirst stent component may be configured for matable attachment to acomplimentary annular projection of a second stent component (i.e., apositioning stent). In turn, the second stent component may be anchoredat the implantation site, for example, to the valve in need ofreplacement and/or adjoining structures.

Alternatively or additionally, in some embodiments the third section ofthe stent component may include at least one attachment element. Eachattachment element of the stent-valve may include, for example, ageometrical opening (e.g., circular or ovular), hook, or strapconfigured for removable attachment to a complimentary structure of adelivery device. In addition, each attachment element may correspond toall or a portion of a commisural post, to which a commissure between twovalve leaflets may be attached. The attachment element(s) may allow thestent-valve to be partially expanded within a patient's body while thestent-valve remains attached to the delivery device. This may allow thestent-valve to be returned to a collapsed configuration and repositionedwithin the patient's body when it is determined that fully expanding thestent-valve would cause the stent-valve to be installed incorrectly.Alternatively or additionally, this may allow the stent-valve to bereturned to the collapsed configuration and removed from the patient'sbody when it is determined that the stent-valve is not functioningproperly (e.g., not permitting sufficient flow). In some embodiments,the stent-valve may include one attachment element. In otherembodiments, the stent-valve may include at least two, three, six, orany other suitable number of attachment elements. In some embodiments,the fully-expanded stent diameter in the region of the attachmentelement(s) may be smaller than the diameter of the region that houses anassociated valve. This may reduce the risk of injury to the patient'sbody (e.g., perforation of the aorta) from the attachment elementsand/or make it easier to affix the attachment elements to thecomplimentary structure of the delivery device.

In some embodiments, the stent component of the stent-valve may includea lattice structure with a plurality of cells. The lattice structure maybe formed from, for example, a shape-memory alloy such as nitinol or anyother suitable material(s). The cells in the lattice structure may bemost densely populated in the section of the stent component thatincludes the fixation element. This may provide added support to thefixation element and increase the stability of the stent-valve. In someembodiments, the lattice structure may form at least one elongate stem(e.g., commissural post) that extends distally along the stent componenttowards the at least one attachment element. The at least one stem mayconnect directly to the at least one attachment element. Alternatively,the lattice structure may form at least one supporting element forconnecting the at least one stem to the at least one attachment element.In some embodiments, all of the cells in the lattice structure may beclosed cells, which may facilitate recapture of the stent-valve from thepartially-expanded configuration to the collapsed configuration.

Still other embodiments of the present invention are directed to amethod for replacing a valve. A stent-valve is provided that includes astent component with an annular groove, and the stent-valve is securedaxially to an annulus of the valve in need of replacement. In someembodiments, providing a stent-valve may include suturing a valvecomponent to the stent component. Alternatively or additionally,providing a stent-valve may include expanding a valve component withinthe stent component in order to form a friction fitting. In someembodiments, providing a stent-valve may include securing a valvecomponent to the stent component with a hook-and-loop (e.g., VELCRO®)fastening system.

In other embodiments of the present invention, a method for replacing avalve is provided whereby a first stent component that includes anannular element is implanted such that at least a portion of the firststent component is housed within a valve in need of replacement. Astent-valve that includes a second stent component is positioned withinthe first stent component by matably attaching a complimentary annularelement of the second stent component to the annular element of thefirst stent component.

In still other embodiments of the present invention, a stent-valvedelivery system is provided. A first assembly is provided that includesan outer sheath and a guide wire tubing. The delivery system alsoincludes a second assembly including a stent holder configured forremovable attachment to at least one attachment element of astent-valve. The stent-valve may be positioned over the guide wire ofthe first assembly. The first assembly and the second assembly may beconfigured for relative movement with respect to one another in order totransition from a closed position to an open position. In the closedposition, the outer sheath may encompass the stent-valve still attachedto the stent holder and thus constrain expansion of the stent-valve. Inthe open position, the outer sheath may not constrain expansion of thestent-valve and thus the stent-valve may detach from the stent holderand expand to a fully expanded configuration.

In some embodiments, the first assembly and the second assembly may beconfigured to transition from the closed position, to a partially-openposition, to the open position. In the partially-open position, thestent-valve may expand partially but not detach from the stent holderbecause the outer sheath may still encompass the at least one attachmentelement of the stent-valve and the stent holder. When the stent-valve isin the partially-expanded configuration, it may be determined whetherthe stent-valve will be positioned correctly if the stent-valve isexpanded to the fully expanded configuration. Alternatively oradditionally, the functionality of the stent-valve may be tested (e.g.,to determine whether the stent-valve will permit sufficient blood-flow)when the stent-valve is in the partially-expanded configuration.

In some embodiments, the stent-valve delivery system may include atleast one balloon (e.g., proximal to the stent-valve or other stent tobe delivered) configured to cause expansion of the stent-valve orpositioning stent upon inflation of the at least one balloon.

In some embodiments, the stent-valve delivery system may include a pushhandle that causes the relative movement of the first assembly and thesecond assembly. Alternatively, the stent-valve delivery system mayinclude a screw mechanism for translating rotational movement of ahandle into the relative movement of the first assembly and the secondassembly.

In some embodiments, the stent-valve delivery system may include anintegrated introducer within which the first assembly and the secondassembly are positioned during delivery of the stent-valve to animplantation site. The integrated introducer may be configured to remainwithin a patient's body even after the first assembly and the secondassembly are removed, for example, to allow for the introduction of anoccluder.

In some embodiments, after expansion of the stent-valve to the fullyexpanded configuration, the delivery system may be configured to returnto the closed position by passing the second assembly through thestent-valve towards a distal end of the first assembly.

Still other embodiments of the present invention are directed to amethod for delivering a stent-valve to an implantation site whereby thestent-valve is removably attached to a delivery device and thestent-valve is delivered to the implantation site in a collapsedconfiguration. The stent-valve may be partially expanded whilemaintaining the stent-valve attached to the delivery device. Adetermination with respect to the stent-valve may be made when thestent-valve is in the partially-expanded configuration. When thedetermination yields a positive response, the stent-valve may beexpanded to its fully expanded configuration by causing the stent-valveto detach from the delivery device.

In one particular embodiment, it may be determined whether thestent-valve is positioned correctly at the implantation site. Thestent-valve may be returned to the collapsed configuration andrepositioned when the stent-valve is not positioned correctly at theimplantation site.

Alternatively or additionally, it may be determined whether a valvecomponent of the stent-valve is functioning properly, for example, bytesting whether the valve component will permit sufficient blood-flow.The stent-valve may be returned to the collapsed configuration andremoved from a patient's body when the stent-valve is not functioningproperly.

In some embodiments, delivering the stent-valve to the implantation sitemay include delivering the stent-valve to the heart for replacement of acardiac valve. The delivery may include accessing a patient's bodythrough an intercostal space (e.g., fifth intercostal space) andpenetrating the left ventricle at the apex of the heart.

In still other embodiments of the present invention, an occluder forsealing an orifice in tissue is provided. The occluder may include afirst portion capable of expansion from a collapsed configuration on aluminal side of the orifice to an expanded configuration. The occluderalso includes a second portion capable of expansion from a collapsedconfiguration to an expanded configuration on a side of the orificeopposite to the luminal side. The first portion and the second portionmay form a central, hollow channel for housing a guide wire.

In some embodiments, the occluder may include a connector for connectingthe occluder to a catheter. For example, the connector may include ahollow screw mechanism for connecting to a threaded catheter. Theoccluder may be housed by a second catheter for delivery to the tissueorifice.

In some embodiments, the top portion of the occluder may include achannel sealing mechanism for preventing blood-flow from the luminalside of the tissue orifice. For example, the channel sealing mechanismmay include a membrane, foam, and/or a valve. Suitable examples of foamand/or membranous materials include polyurethane and gelatin.

In some embodiments, the top portion of the occluder may include a firstmaterial and the bottom portion of the occluder may include a secondmaterial, where the second material may be coarser than the firstmaterial. This may facilitate the formation of scar tissue on the outerportion and speed the heeling process. For example, the first and/orsecond materials may include felt(s) and/or velour(s) made from Teflon,Dacron, polyurethane, polydioxanone, polyhydroxybutyrate, and/or othermaterial.

In other embodiments of the present invention, a method for sealing anorifice in tissue is provided whereby an expandable and collapsibleocclusion device is connected to a first catheter. The occlusion devicemay be inserted into a second catheter in a collapsed condition. Thefirst catheter and a central channel of the occlusion device may receivea guide wire. The second catheter may be positioned in the orifice, suchthat a first end of the second catheter is positioned on a luminal sideof the orifice. Relative movement between the collapsed occlusion deviceand the second catheter may be caused in order to move the occlusiondevice out of the second catheter. Upon the occlusion device emergingfrom the first end of the second catheter, a first portion of theocclusion device may expand on the luminal side of the orifice. Upon theocclusion device being completely emerged from the second catheter, asecond portion of the occlusion device may expand.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the following description, taken in conjunction with the accompanyingdrawings, in which like reference characters refer to like partsthroughout, and in which:

FIG. 1A shows a valve component in an expanded configuration accordingto some embodiments of the present invention;

FIG. 1B shows a valve component in a collapsed configuration accordingto some embodiments of the present invention;

FIG. 2A shows a stent component in an expanded configuration accordingto some embodiments of the present invention;

FIG. 2B shows a single-stent-valve, that includes a stent component anda valve component, in an expanded configuration according to someembodiments of the present invention;

FIG. 2C shows a single-stent-valve a collapsed configuration accordingto some embodiments of the present invention;

FIG. 3A shows a stent component in an expanded configuration accordingto some embodiments of the present invention;

FIG. 3B shows a stent component in a collapsed configuration accordingto some embodiments of the present invention;

FIG. 4 shows a double-stent-valve, that includes two stent componentsand a valve component, in an expanded configuration according to someembodiments of the present invention;

FIGS. 5A-7B illustrate the use of a single-stent-valve to replace afailed biological (artificial) valve according to some embodiments ofthe present invention;

FIGS. 8A and 8B show a stent component that includes attachment elementsfor securing the stent to a delivery device and fixation elements forsecuring the stent at the implantation site according to someembodiments of the present invention;

FIG. 8C shows a stent component having a diameter in the region of theattachment element(s) that is smaller than the diameter of a stentregion that houses an associated valve, according to some embodiments ofthe present invention;

FIG. 8D shows a stent component that includes independently bendableelement(s) for use in positioning/securing the stent to thegeometry/topology at an implantation site according to some embodimentsof the present invention;

FIG. 8E shows a stent component that includes locking elements in acrown configuration and a fixation element for securing the stent at animplantation site according to some embodiments of the presentinvention;

FIG. 8F shows a stent component that includes multiple struts forcarrying a valve component more closely to a region of the stentcomponent that includes attachment element(s) for attaching the stentcomponent to a delivery device;

FIGS. 9A-16 show additional embodiments of stent components that includeattachment elements for securing the stent to a delivery device and/orfixation elements for securing the stent at the implantation siteaccording to the present invention;

FIGS. 17/18, 19, and 20 show additional examples of double-stent-valvesaccording to some embodiments of the present invention;

FIG. 21A shows a stent-valve in the shape of an opposed double crownaccording to some embodiments of the present invention;

FIGS. 21B-E show views of a double-conical stent in accordance with someembodiments of the present invention;

FIGS. 22A-22D show a delivery system for delivering a self-expandingstent-valve to an implantation site according to some embodiments of thepresent invention;

FIGS. 23A-23D show a delivery system with inflatable balloon(s)according to some embodiments of the present invention;

FIGS. 24A-24D show a delivery system having a proximal outer shaft withan increased diameter according to some embodiments of the presentinvention;

FIGS. 25A-25C show a delivery system with inflatable balloon(s)according to some embodiments of the present invention;

FIGS. 26A-26C show a delivery system with an integrated introduceraccording to some embodiments of the present invention;

FIG. 27 is a flowchart of illustrative stages involved in replacing afailed native or artificial valve according to some embodiments of thepresent invention;

FIGS. 28A-C illustrate the replacement of a failed valve through the useof a delivery system according to some embodiments of the presentinvention;

FIGS. 29A and 29B show a guide wire compatible occluder for sealing anaccess orifice according to some embodiments of the present invention;

FIG. 30 shows a guide wire for guiding the delivery of an occluderand/or stent-valve according to some embodiments of the presentinvention;

FIG. 31 shows a threaded catheter for attachment to and use inpositioning an occluder according to some embodiments of the presentinvention;

FIGS. 32A and 32B show a delivery system for an occluder according tosome embodiments of the present invention; and

FIGS. 33A and 33B show an occluder positioned within an access orificeaccording to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-3B show components 100, 200, and 300 for use in replacing, forexample, a failed (e.g., degenerated) aortic valve, mitral valve, orpulmonary cardiac valve (e.g., in a pediatric patient) in accordancewith some embodiments of the present invention. More particularly, FIGS.1A and 1B show a valve component 100. FIGS. 2A-2C show a stent component200 for housing valve component 100. FIGS. 3A and 3B show a stentcomponent 300 for housing stent component 200 and valve component 100. Adevice that includes components 100 and 200 may be referred to as asingle-stent-valve. A device that additionally includes component 300may be referred to as a double-stent-valve.

FIG. 4 shows a double-stent-valve 400 that includes valve component 100,stent component 200, and stent component 300 in accordance with someembodiments of the present invention. Double-stent-valve 400 may replacea failed native or artificial valve. As used herein, a “native valve”refers to a valve naturally present within a patient's body. A failednative valve may be, for example, a stenotic valve. An “artificialvalve” refers to a biological or synthetic (e.g., mechanical) valveintroduced into the patient's body through surgery. The implantationsite for a device 400 (or other replacement valve) typically includes atleast a part of the area within the failed valve and/or along at least aportion of adjacent structure(s). For example, to replace a failedaortic valve, device 400 may be implanted within the patient's body suchthat portion 402 of the device is positioned substantially entirelywithin the failed aortic valve. Portion 404 of device 400 may extendalong at least a portion of the aorta. Portion 406 of device 400 mayextend into at least a portion of the left ventricle of the patient'sheart.

Double-stent-valve 400 may be delivered to the implantation site usingany suitable delivery approach. In some embodiments of the presentinvention, device 400 may be substantially entirely assembled fromcomponents 100, 200, and 300 outside the patient's body before device400 is delivered to the implantation site. In other embodiments of thepresent invention, components 100, 200 and 300 of device 400 may bedelivered to the implantation site separately in multiple steps. Forexample, stent component 300 may be delivered and installed at theimplantation site, followed by the delivery and installation of stentcomponent 200 and valve component 100 in one or more separate steps. Inone embodiment, components 100 and 200 may be assembled outside thepatient's body and then delivered and installed within component 300 atthe same time. In another embodiment, stent component 200 may bedelivered and installed within stent component 300, followed by thedelivery and installation of valve component 100 in a separate step.Additional embodiments of double-stent-valves are described inconnection with FIGS. 17-20.

In some embodiments of the present invention, a single-stent-valve (FIG.2B) that includes valve component 100 and stent component 200 (but notstent component 300) may be used to replace a failed native orartificial valve. For example, in one particular embodiment, thesingle-stent-valve may replace a failed biological valve introduced to apatient's body during a prior valve replacement surgery. Thus, thesurgery involving the single-stent-valve shown in FIG. 2B may be asecondary or subsequent valve replacement surgery. Although in thisembodiment no new stent component 300 may be introduced to the patient'sbody, the single-stent-valve including components 100 and 200 may behoused by a stent and/or valve remaining at the implantation site fromthe prior valve replacement surgery. In some embodiments, at least aportion of the stent and/or valve from the prior surgery may be removedbefore the single-stent-valve is installed at the implantation site.Additional details regarding the replacement of a failed biologicalvalve with a single-stent-valve are described in connection with FIGS.5A-7B.

In some embodiments of the present invention, valve component 100 may beflexible and collapsible such that it can be collapsed, for example,during delivery via a catheter to the implantation site. Variousembodiments of delivery systems and surgical approaches forminimally-invasive surgery are described below in connection with FIGS.22-27C. Upon delivery, the valve component may be at least partiallyexpanded. FIG. 1A is a perspective view of valve component 100 in anexpanded configuration. FIG. 1B is a perspective view of valve component100 in a collapsed configuration. As used herein, “collapsedconfiguration” and “expanded configuration” refer to a relativedifference in, for example, the diameter and/or any other physicalcharacteristic(s) of a component (e.g., length, width). For example, thecollapsed valve component shown in FIG. 1B has an reduced diameter andmay or may not have a longer length than the expanded valve componentshown in FIG. 1A.

Valve component 100 may include a biological material (e.g., tanned,untanned, heterologous or autologous), non-biological material, asynthetic material (e.g., polymer(s) such as polyurethane and/orsilicon(es)), or a combination thereof. In some embodiments, valvecomponent 100 may include preserved biological tissue such as, forexample, human tissue (e.g., homografts, autografts of valve tissue) oranimal tissue (heterograft or xenograft valve tissue). In someembodiments, valve component 100 may be a mechanical valve. For example,when valve component 100 is a biological valve, expansion of valvecomponent 100 from a collapsed configuration to an expanded may requireself-expansion of an affixed stent component 200. In contrast, asynthetic valve component 100 may be capable of self-expansion. Valvecomponent 100 may have a shape/form (e.g., length, width, diameter,etc.) corresponding to that of the intended valve application (e.g.,tricuspid, pulmonary, mitral or aortic). In FIGS. 1A and 1B, valvecomponent 100 is a tricuspid valve with three flaps. This particularconfiguration may be particularly suitable, for example, for replacing afailed aortic valve. In other embodiments, valve component 100 may haveany other suitable number of flaps and/or other physical characteristics(e.g., diameter, length, width, etc.).

FIG. 2A is a perspective view of stent component 200 in accordance withan embodiment of the present invention. As shown in FIG. 2B, stentcomponent 200 houses valve component 100. In some embodiments, at leasta portion of stent component 200 may be substantially cylindrical inshape. Alternatively or additionally, stent component 200 may have anindentation (e.g., annular groove) or other fixation element 202, forexample, for fixing the stent in place at the implantation site. Forexample, when stent component 200 is part of double-stent-valve 400(FIG. 4), fixation element 202 may matably attach to a complimentaryfixation element 302 (e.g., inward annular projection, FIG. 3A) of stentcomponent 300. When stent component 200 is part of a single-stent valve(FIG. 2B), fixation element 202 may affix to at least a portion of thefailed valve. Additional embodiments of stent components that mayinclude fixation elements are described in connection with FIGS. 6A and8A-16.

In some embodiments of the present invention, stent component 200, likevalve component 100, may be capable of at least two configurations: afirst, collapsed configuration (e.g., during delivery) and a second,expanded configuration (e.g., after installation). FIG. 2A shows stentcomponent 200 in an illustrative expanded configuration. FIG. 2C showsstent component 200 in an illustrative collapsed configuration, with thecollapsed valve component 100 housed therein, for example, for deliveryof both components to the implantation site at the same time. In someembodiments, stent component 200 may be made from wire or may be lasercut from a tube, sheath, or the like. Stent component 200 may include ashape-memory alloy material such as, for example, nitinol. Theshape-memory alloy may allow for compression of stent component 200(and/or valve component 100) into the first configuration for, forexample, delivery through a small opening in the patient's body andexpansion of stent component 200 to the second configuration duringinstallation. Components 100 and/or 200 may be held in the collapsedconfiguration, for example, with a sheath or wrap. The sheath/wrappingmay be removed in order to allow components 100 and/or 200 toreconfigure into the second configuration.

Valve component 100 may be secured to stent component 200 via anysuitable securing mechanism or combination of securing mechanisms. Forexample, in one embodiment, valve component 100 may be sutured with oneor more stitches to stent component 200. In another embodiment, valvecomponent 100 may be secured to stent component 200 by way of a frictionfitting. For example, valve component 100 may have a fully-expandeddiameter that is slightly larger than the expanded diameter of stentcomponent 200 such that components 100 and 200 fit securely togetherupon expansion of component 100 within component 200. In yet anotherembodiment, a hook-and-loop type (e.g., VELCRO®) fastening system may beused to secure valve component 100 to stent component 200. For example,stent component 200 may include microscopic hooks and valve component100 may include corresponding microscopic loops (or vice-versa). Thishook-and-loop fastening system may include a micro-velour material,which has been used previously for surgical applications to improvetissue in-growth. Such a hook-and-loop fastening system may allow theposition of valve component 100 to be fine-tuned relative to theposition of stent component 200, for example, after components 100 and200 have been implanted within a patient's body. The hooks/loops mayalso facilitate blood clotting and the formation of a seal at theinterface between valve component 100 and stent component 200. To avoidpremature clot formation (e.g., excessive clot formation beforeinstallation is complete), anti-coagulation monitoring and/or treatmentmay be provided to the patient. Reliable hook-and-loop connections maystill be achieved in the presence of premature clot formation, althoughhigher activation pressure (described below) may be required. Apreliminary evaluation shows that reliable hook-and-loop connections canbe formed in the presence of water, jelly, liquid soap, and/orcoagulating proteins. In some embodiments, such a hook-and-loopfastening system may be used, alternatively or additionally, to securestent component 200 to stent component 300 (e.g., with the microscopichooks attached to an exterior surface of stent component 200 and thecorresponding microscopic loops attached to an interior surface of stentcomponent 300, or vice versa).

Any suitable mechanism or combination of mechanisms (e.g., direct orindirect exertion of mechanical compression) can be used to supply theactivation pressure required to cause the micro-hooks to attach to themicro-loops. For example, in some embodiments, one or more balloons maybe positioned adjacent to valve component 100 and/or stent component 200(e.g., within valve component 100) and inflated temporarily to bring themicro-hooks into contact with the micro-loops. Such balloon(s) mayplaced within the valve component 100 and/or stent component 200subsequent to delivery of the stent and/or valve to the implantationsite. Alternatively, in some embodiments the balloon(s) can be mounted(e.g., removably mounted) within the valve component 100 and/or stentcomponent 200 prior to delivery of the stent and/or valve to animplantation site (e.g., prior to loading the stent and/or valve into adelivery device). The use of such balloon(s) is not limited toembodiments in which the valve and stent are affixed to one another byway of hooks/loops. Rather, such balloon(s) may be used whenever it isnecessary or desirable to use the balloon(s) to aid in the expansionand/or engagement at the implantation site of the stent and/or valve(e.g., when the valve is sutured to the stent). In some embodiments, aself-expanding valve component 100 may be provided that self-expandswithin stent component 200 in order to cause the micro-hooks to contactthe micro-loops.

FIG. 3A is a perspective view of stent component 300 in accordance withan embodiment of the present invention. As described above, stentcomponent 300 may have a fixation element 302 (e.g., inward annularprojection) that matably attaches to a complimentary fixation element202 of stent component 200 (FIG. 2A). FIG. 4 shows an embodiment of suchmatable attachment, in which component 300 houses both components 100and 200 to form double-stent-valve 400. The geometry (e.g., length,width(s), diameter(s), etc.) of stent component 300 may be particularlysuited, for example, for aortic valve replacement. In other embodiments,other geometries and configurations of stent component 300 may beprovided.

Stent component 300 may be secured in place at the implantation siteusing any suitable securing mechanism or combination of securingmechanisms. For example, in some embodiments, fixation element 302 mayform a recess (e.g., exterior annular groove) for receiving at least aportion of the failed valve. In some embodiments, stent component 300may have a diameter slightly larger than a diameter of the implantationsite such that delivery and expansion of stent component 300 at theimplantation site secures stent component 300 in place by way of afriction fitting. In some embodiments, stent component 300 may includeone or more projections (e.g., spikes) or clasps for anchoring stentcomponent 300 to the failed valve and/or adjacent structure(s) at theimplantation site.

FIGS. 5A-7B illustrate embodiments of the present invention forreplacing a failed artificial (e.g., biological) valve (e.g.,stent-valve) introduced to a patient's body during a prior surgery. FIG.5A is a perspective view of a failed biological valve 500 where leaflets502 of the valve fail to close. FIG. 5B is a perspective view of thefailed biological valve 500 after implantation of the stent-valve shownin FIG. 2B. As shown, failed biological valve 500 (e.g., and/or itsaccompanying stent) secure the new stent-valve in place at theimplantation site. More particularly, fixation element 202 of thestent-valve (FIGS. 2A and 2B), which may be an annular groove formingthe narrowest portion of the stent-valve, may receive the annulus offailed biological valve 500 thereby securing the stent-valve in place.In other embodiments of the present invention, at least a portion offailed biological valve 500 may be removed from the patient's body(e.g., the failed valve itself), whereas other portion(s) of the failedvalve may be left behind at the implantation site (e.g., a supportingstent). In still other embodiments, the failed biological valve 500including all of its associated component(s) may be substantiallyentirely removed from the implantation site prior to installation of thenew stent-valve.

FIG. 6A is a perspective view of another example of a stent-valve 600 inaccordance with an embodiment of the present invention. FIG. 6B is aperspective view showing a use of stent-valve 600 to replace a failedartificial (e.g., biological) valve. Stent-valve 600 includes one ormore (e.g., three) locking or retaining elements 602 along an outersurface of the stent component. Each locking element 602 may includedirectionality such that it collapses (e.g., becomes flush with an outersurface of the stent component) upon engagement of the locking elementwith another surface (e.g., the interior of a catheter). When a lockingelement 602 protrudes from the outer surface of the stent component, afirst end 604 of the locking element may be adjacent to the outersurface of the stent component, while a second end 606 of the lockingcomponent may be spaced apart from the outer surface of the stentcomponent. When multiple locking elements 602 are provided, first ends604 of all the locking elements may be positioned at substantially thesame vertical height/position along the central axis of the stentcomponent (e.g., albeit dispersed evenly around the perimeter of thestent component), and second ends 606 may be positioned at differentvertical height(s)/position(s) than first ends 604. First end 604 may beflexible (e.g., allowing hinge-like movement in two dimensions) suchthat movement of the second end relative to the outer surface of thestent component does not impair the locking mechanism.

In some embodiments of the present invention, stent-valve 600 may beinserted into the interior of the failed valve in the direction of arrow608 in FIG. 6B. When first end 604 of each locking element 602encounters the interior diameter/annulus of the failed valve, second end606 of the locking element may collapse toward the outer surface of thestent component. Upon second end 606 of the locking element reaching anopen area of the failed valve, the second end may jut outwardly, lockingstent-valve 600 in place. Thus, locking elements 602 may provide amechanism for securing the new stent-valve in place, as an alternativeto or in addition to fixation element 610 (e.g., annular groove) of thestent component for affixing stent-valve 600 to (for example) theannulus the failed valve.

FIGS. 7A and 7B show another embodiment of a stent component 700 withlocking elements in accordance with the present invention. FIG. 7A showsthat such a stent component can be made from, for example, a sheet ofsuitable material (e.g., nitinol). Referring to FIG. 7B, stent component700 includes one or more locking elements 702 that extend radially froman outer surface of the stent component such that, for each lockingelement, first end 704 and second end 706 of that locking element havesubstantially the same vertical position/height along the central axisof the stent component. In other embodiments, such locking elements maybe slightly angled, such that ends 704 and 706 of the same lockingelement have different relative vertical positions/heights along thecentral axis of the stent component. In some embodiments, a stentcomponent may be provided that includes multiple locking elements, witheach locking element having ends 704 and 706 with different angularorientations. Different locking elements 702 may have the same ordifferent vertical positions/heights along the central axis of the stentcomponent.

FIGS. 8A-16 show additional examples of suitable stent components foruse in valve replacement in accordance with some embodiments of thepresent invention. These stent components may be used, for example, aspart of single-stent-valves and double-stent-valves. Each of these stentcomponents includes one or more attachment elements for removablyattaching the stent component (e.g., together with an integrated valvecomponent) to a delivery device (FIGS. 22-26). In some embodiments,these stent components may also include a fixation element (e.g.,similar to fixation element 202 (FIG. 2A)) for fixing the stentcomponent in place at the implantation site.

FIG. 8A shows a perspective view of a stent component 800 in a collapsedconfiguration, as well as an as-cut view of stent component 800 thatillustrates details regarding its structure. FIG. 8B shows stentcomponent 800 in an expanded configuration. Stent component 800 includesfirst (e.g., proximal) section 802 that includes a fixation element(e.g., annular groove), second section 804 that may follow the contourof a valve component to be housed therein, and third (e.g., distal)section 806 that includes one or more (e.g., three) attachment elements808. In some embodiments, stent component 800 may include (for example)a lattice structure (e.g., formed from nitinol wire), for example, withsection 802 having a denser population of lattice cells than section 804and/or section 806. This may provide added support to the fixationelement in section 802 and therefore increase the stability of device800 at the implantation site. In some embodiments, stent component 800may include only closed lattice cells in order to facilitate therecapture of stent component 800 by a delivery device when stentcomponent 800 is in a partially-expanded configuration (describedbelow).

In some embodiments, each of attachment elements 808 may include anopening (e.g., circular or ovular) for removably attaching stentcomponent 800 to a complimentary element (e.g., wire, strap or hook) ofa delivery device. Attachment elements 808 may allow for partialexpansion of the stent component (e.g., together with an integratedvalve component and/or another stent component) within a patient's bodywhile causing the stent component to remain attached to the deliverysystem. For example, sections 802 and 804 (e.g., and part of section806) of stent component 800 may expand when stent component 800 ispartially released from a shaft during delivery, whereas no change maybe observed to the relative positions of attachment elements 808 stillconstrained by the shaft (e.g., see FIG. 27 “partial release”). This mayallow a surgeon to reposition and/or test the functionality of thestent-valve (or double-stent-valve) within the patient's body beforefinalizing deployment of the stent-valve at the implantation site. Suchtesting of the valve functionality may include peripheral pulsemonitoring, whereby a pulse wave is measurable if the valve isfunctioning properly. A more reliable assessment of the stent valvefunction can be made with transesophageal echocardiography (TEE),intravascular ultrasound (IVUS) and/or intracardiac echocardiography(ICE). If the stent-valve malfunctions during the test (e.g., if thevalve does not permit sufficient blood-flow), the stent-valve may befully recaptured by the delivery device and retrieved from the patient'sbody. In other embodiments, stent component 800 may have a differentlattice structure, attachment elements 808 may be reduced or enlarged inlength and/or other dimension(s), and/or attachment elements 808 may beincluded in other location(s) relative to stent component 800 (e.g.,within section 804).

FIG. 8C shows another embodiment of a stent component with integratedattachment elements 814 that are configured such that the fully expandeddiameter in the region of the attachment element(s) is smaller than thediameter of the region that houses an associated valve. As shown in thisexample, the attachment elements project partially inwardly toward thecenter axis of the stent component. This may reduce the risk of injuryto the patient's body (e.g., perforation of the aorta) from theattachment elements. Alternatively or additionally, this may make iteasier to affix the attachment elements to a complimentary structure ofthe delivery device. For example, when the device is collapsed forattachment to the delivery device, the reduced diameter within theregion of the attachment elements may cause the attachment elements toengage the stent holder earlier.

FIG. 8D shows yet another embodiment of a stent component in accordancewith the present invention. In this embodiment, the first (proximal)section of the stent includes 27 independent, bendable elements 816,each of which may include connected and/or disconnected cell(s) whichcan be open and/or closed. In this embodiment, each bendable elementincludes a single, closed cell. In other embodiments, other number(s)and/or configuration(s) of the bendable elements may be provided.Bendable elements 816 allow for accurate positioning/securing of theproximal stent section to the geometry/topology of (for example) acalcified annulus/failed biological valve. Each element 816 canbend/adapt independently to the topology of the immediately adjacentportion of the calcified annulus/failed biological valve. Bendableelements 816 collectively form an annular groove in which the locationof the bending deformation (grooved portion) for each bendable elementis controlled by reducing or elongating the lengths of an attached pairof stent struts (818, 820) which act as a joint. The length of a singlestent strut is shown by numeral 822. Primarily, the radialforce/resistance of each bendable element 816 is influenced by theselection of angle 824 during stent manufacturing. Other designparameters such as strut thickness/width also influence the radialforce. An advantage of this design is that the stent proximal sectioncan more adequately anchor the stent in place at the implantation siteindependently of the stent mid section. Thus, the stent mid section canbe designed to accommodate (for example) the aortic valve without anyover sizing, therefore reducing the risk of valve failure due to longterm mechanical stress. The stent of FIG. 8D also includes compensationelement 826 (e.g., including a triangular wave portion and two elongatearms) for accommodating elongation mismatch (if any) within the stentduring manufacturing and/or crimping. Contrast FIG. 8D with theembodiment shown in FIG. 8C, in which the absence of dedicated pairs ofstruts prevents the stent proximal section from having elements thatbend independently (e.g., during implantation).

FIG. 8E shows another embodiment of a stent component in accordance withthe present invention. In FIG. 8E, only about ⅓ of an as-cut view of thestent component is shown in order to more clearly show its features.Similar to the locking/retaining elements 602 shown in FIGS. 6A and 6B,the stent component shown in FIG. 8E includes a plurality ofindependently bendable locking elements 828 generally located within theregion of the stent component referenced as region 804 in FIG. 8B.Locking elements 828 form a crown that may engage, for example, a failedbiological valve or calcified native annulus from the outflow side. Thestent component in FIG. 8E also includes fixation element 830 (e.g.,annular groove). In FIG. 8E, locking elements 828 are shown as beingpositioned at substantially the same position/height along the centralaxis of the stent component. In other embodiments, different lockingelements 828 may have the same or different vertical positions/heightsalong the central axis of the stent component similar to, for example,the stent shown in FIG. 7B. Having different positions/heights for atleast some of locking elements 828 may facilitate engagement with, forexample, native valves of different sizes (e.g., a thin native valvewhich can be engaged by locking elements separated by a small distanceor a thick native valve which can only be engaged by more distantlyspaced locking elements).

FIG. 8F shows another embodiment of a stent component in accordance withthe present invention. In FIG. 8F, only about ⅓ of an as-cut view of thestent component is shown in order to more clearly show its features.FIG. 8F includes a Dacron pocket 832 for housing a valve component,where Dacron pocket 832 is sutured along the valve free edge 834. Asshown, the valve component within pocket 832 is housed more closely toattachment element(s) 836, which are similar to attachment elements 808in FIG. 8B, in the embodiment of FIG. 8F than in the embodiment shown inFIG. 9C. A middle inverted U-shaped strut 838 is slid into Dacron pocket832. The valve/pocket is sutured to an outer inverted U-shaped strut840. Inner U-shaped strut 842 is positioned outside Dacron pocket 832and serves as a skid during loading/releasing/recapturing of the implantwith a delivery device by reducing the friction forces between Dacronpocket 832 and the outer sheath Inner U-shaped strut 842 may also besutured to Dacron pocket 832. In some embodiments, Dacron pocket 832 maybe closed with further stitching 844. Although the bottom portion of thestent is not shown in FIG. 8F, in some embodiments it may include, forexample, a fixation element (e.g., annular groove) similar to fixationelement 802 in FIG. 8B.

FIGS. 9A-9C show another example of a stent component 900 withintegrated attachment element(s) 902 in accordance with an embodiment ofthe present invention. FIG. 9A shows a perspective view of stentcomponent 900 in a collapsed configuration, as well as an as-cut view ofstent component 900 that illustrates details regarding its structure.FIG. 9B is a perspective view of stent component 900 in an expandedconfiguration. FIG. 9C shows stent component 900 (with an integratedvalve component) positioned beside a ruler to show its size (e.g., about4 centimeters). As shown, each of attachment elements 902 includes acircular or ovular opening attached to stent component 900 by twosupporting elements 904 (e.g., wires). In turn, each pair of supportingelements 904 attaches to a stem 906 (e.g., commissural post) within thelattice structure. In contrast, each of the attachment elements 808 inFIG. 8B attaches to stent component 800 by a single supporting element810, and each supporting element 810 is attached to a stem 812. All ofthe stent components shown in FIGS. 8A-16 include three stems, althoughit will be understood that other suitable numbers of stems or no stemsat all (e.g., FIG. 2A) may be provided in accordance with someembodiments of the present invention. Stent component 900 also includesa fixation element 908, which may be substantially similar to fixationelement 202 (FIG. 2A). In the embodiment of FIG. 9C, the valve componentis sutured around the circumference of its annulus. Each of the threeleaflets of the valve component is also spot-sutured to the stent topermit valve functionality. The locations of the sutures may be selectedin order to permit elongation of the stent during crimping withoutdamaging the valve or suture. For example, the inflow of stent (e.g.,within region 802 shown in FIG. 8B) may be covered on its inner sidewith a cloth (e.g., mesh). The cloth and valve component may be suturedto the stent (e.g., using a running and/or interrupted technique) in theregion adjacent to the annular groove (e.g., along the border of stentsections 802 and 804 in FIG. 8B). Some excess cloth on the inflow sidemay be folded over onto the exterior side of the stent and suturedtogether with the valve component in the vicinity of (e.g., furthertowards section 804) the previous suturing location. The commissures ofthe valve component may also be attached to the corresponding stentposts, which may have previously been covered with cloth (e.g., Dacron).Alternatively, pericardium or other suitable material can be used tocover the stent component. In some embodiments, the valve component maybe a porcine valve component which may be harvested as such or assembledfrom various donors in order to have an optimal match between threecusps. Bovine and equine valves may also be used that are made frompericardium. Other suitable sources of valve components can also beused.

FIGS. 10A-10B show yet another example of a stent component 1000 withintegrated attachment element(s) 1002 in accordance with an embodimentof the present invention. FIG. 10A shows a perspective view of stentcomponent 1000 in a collapsed configuration, as well as an as-cut viewof stent component 1000 that illustrates details regarding itsstructure. FIG. 10B is a perspective view of stent component 1000 in anexpanded configuration. As shown, at least one pair (e.g., all pairs) ofattachment elements 1002 are attached to one another with a bracingelement 1004. Each bracing element 1004 may attach on one end to a firstattachment element 1002 and on the other end to a second attachmentelement 1002. In some embodiments, the bracing element(s) 1004 mayinclude a wire shaped like a triangular wave. When all attachmentelements 1002 include a bracing element 1004, collectively the bracingelements 1004 may form a circle around the perimeter of stent component1000. Stent component 1000 may be substantially the same as stentcomponent 800 (FIG. 8B) in all other respects.

FIGS. 11-16 show additional examples of stent components with integratedattachment element(s) in accordance with some embodiments of the presentinvention. Each of FIGS. 11-16 includes a perspective view of a stentcomponent in a collapsed configuration, as well as an as-cut view of thestent component that illustrates details regarding its structure. Thefollowing description summarizes various features of the stentcomponents shown in FIGS. 11-16. Additional structural features of theembodiments shown in FIGS. 8A-16 will be apparent to one of ordinaryskill in the art from the drawings.

FIG. 11 shows a stent component that includes shorter supportingelement(s) for attaching to a corresponding number of ovular/circularattachment element(s) (i.e., shorter in comparison to supportingelements 810 of FIG. 8B). The stem(s) in FIG. 11 for attaching to thesupporting elements may be substantially the same as stems 906 in FIG.9B.

FIG. 12 shows a stent component that includes two supporting elementsfor attaching to each ovular/circular attachment element. Each pair ofsupporting elements attaches to a stem such that collectively thesupporting elements and stem form a second ovular/circular opening, forexample, for added support and/or for use as an additional oralternative attachment element. The stem(s) in FIG. 12 may besubstantially the same as stems 906 in FIG. 9B.

FIG. 13 shows a stent component that includes non-circular/ovularattachment components such as, for example, wires, hooks, straps, or acombination thereof for matably attaching to a complimentary element ofa delivery device (e.g., a circular or ovular opening). The stentcomponent in FIG. 13 also includes an increased number of attachmentelements (e.g., six) when compared to the number of attachment elements(e.g., three) of stent component 900 (FIGS. 9A and 9B). In FIG. 13, theattachment elements attach directly to the stems of the stent component,two attachment elements per stem. The stem(s) in FIG. 13 may besubstantially the same as stems 906 in FIG. 9B.

FIG. 14 shows a stent component that replaces the wire/hook attachmentelements in FIG. 13 with long, narrow openings (e.g., long and narrow incomparison to attachment elements 902 of FIG. 9A). The stem(s) in FIG.14 may be substantially the same as stems 906 in FIG. 9B.

FIG. 15 shows a stent component with a modified lattice structure,including a modified stem structure. The stent component in FIG. 15 alsoincludes circular/ovular attachment elements, where each attachmentelement is attached to a stem by two supporting elements. Each pair ofsupporting elements and corresponding stem may form a secondcircular/ovular opening, in a manner similar to the supportingelement/stem configuration shown in FIG. 12.

FIG. 16 shows a stent component with attachment elements modifiedrelative to the attachment elements shown in FIG. 15. Each attachmentelement in FIG. 16 includes a wire (e.g., a “U”-shaped wire), with bothends of the wire attaching directly to the same stem such that theattachment element/stem configuration forms a substantiallyovular/circular opening. The stem(s) in FIG. 16 may be substantially thesame as the stems shown in FIG. 15.

FIGS. 17/18, 19 and 20 show additional examples of double-stent-valvesin accordance with some embodiments of the present invention.Single-stent valve 1700 of FIG. 17 includes stent 1702 and valvecomponent 1704. FIG. 18 shows a double-stent valve that includesstent-valve 1700 and positioning stent 1802, which may be attachedtogether by way of (for example) an annular groove and correspondingannular recess. Stent component 1802 may be covered with, for example,pericardium in order to prevent paravalvular leaking. Thedouble-stent-valve of FIG. 18 may have a generally cylindrical shapethat is suitable for, for example, pulmonary and/or aortic applications.

Now referring to FIGS. 19 and 20, FIG. 19 shows a double-stent-valvewith first stent 1902, second stent 1904, and valve component 1906. FIG.20 shows a double-stent-valve with first stent 2002, second stent 2004,and valve component 2006. Again, the positioning stents in FIGS. 19 and20 may be covered (e.g., with pericardium) in order to preventperivalvular leaking. The stents of FIGS. 19 and 20 may be suitable for,for example, pulmonary valve replacement (e.g., in the presence of ananeurysm that creates a deformation and where there is no suitable rimfor placement of a grooved stent-valve). More particularly, with respectto pulmonary valve applications, many candidates for pulmonary valvereplacement have an aneurysm there or a funnel-type configuration at theinflow or at the outflow. Thus, the first stent 1902 or 2002 can adaptto this funnel-type pulmonary artery configuration and provide the roundorifice for securing the stent-valve (1904, 1906) or (2004, 2006). Insome embodiments, a double-stent-valve similar to the double-stent-valveof FIG. 20 may be provided that is suitable for mitral and/or tricuspidvalve applications, where the positioning stent has a reduced height andan oval configuration that provides a round rim for attachment to agroove of a stent-valve (alternatively, a hook-loop fastening system canbe used). Alternatively or additionally, the positioning stent may haveindependently bendable elements that provide a secure fit at theimplantation site. Additional structural features of the embodimentsshown in FIGS. 17-20 and details regarding their use for valvereplacement will be apparent to one of ordinary skill in the art fromthe drawings.

FIG. 21A shows another example of a stent-valve 2100 in accordance withsome embodiments of the present invention. The embodiment shown in FIG.21A may be suitable for, for example, mitral valve replacement.Stent-valve 2100 may be assembled from a stent component and a valvecomponent outside the patient's body prior to delivery of stent-valve2100 to an implantation site. Stent-valve 2100 may be a self-expandingstent-valve adapted for replacement of the mitral valve. As shown,stent-valve 2100 may have a shape similar to an opposed double crown.Stent-valve 2100 may include a porcine pulmonary valve 2102 sutured intoa Dacron conduit (prosthetic tube), with two self-expanding nitinolZ-stents 2104 and 2106 sutured on the external surface of the prosthesisin such a way to create two self-expanding crowns. The self-expandingstent-valve may be loaded for delivery into a Teflon sheath, or othersuitable delivery system. In this embodiment, Dacron is used to coverthe stent, although in other embodiments other materials such as Teflon,silicon, pericardium, etc. may be used. In one surgical approach, anincision of 1 centimeter may be made on the left atrium, controlled bypurse string sutures. The Teflon sheath with loaded stent may be pushedalong a guide wire (the atrium having been punctured with a needle andthe guide wire inserted) until the middle of stent-valve reaches themitral annulus. Then, the sheath may be pulled back to deploy theventricular side first, followed by total removal of the sheath toexpose the atrial side. Additional details regarding stent-valve 2100and a surgical approach for delivering it to an implantation site aredescribed in Liang Ma et al., “Double-crowned valved stents for off-pumpmitral valve replacement”, European Journal of Cardio-Thoracic Surgery28:194-199, Jun. 13, 2005, which is incorporated by reference herein inits entirety.

FIGS. 21B-E show views of a double-conical stent in accordance with someembodiments of the present invention. Referring to FIGS. 21B and 21C,the double-conical stent may include a substantially cylindrical stent2108 carrying a valve 2110 as well as two substantially conical stents(2112, 2114) affixed/attached to stent 2108 (e.g., with VELCRO®,suture(s), friction fitting(s), other suitable affixing mechanism(s), ora combination thereof). FIG. 21D shows a cross-section of thedouble-conical stent shown in FIGS. 21B and 21C. In other embodiments,at least one of stents 2112 and 2114 may have a crown-shape withprotruding spikes formed from open or closed cells or Z-stents. Thefirst and second additional stents (2112, 2114) may collectively form afixation element 2116 (FIG. 21C; e.g., annular groove) similar tofixation element 202 shown in FIG. 2A. Fixation element 2116 may allowfor fixation, for example, in an orifice of a failed valve which is ofsimilar size as the stent 2108 carrying valve component 2110 or to ananchoring stent with a complimentary annular projection. In someembodiments, stents 2112 and 2114 (and optionally stent 2108) may bereplaced with a single stent in a double-conical configuration (e.g.,the two cones connected by a continuous region in the area of fixationelement 2116). An advantage to using separate stent(s) for thecones/fixation element is that the mechanical stresses of thecones/fixation element (e.g., first and second stents 2112 and 2114) canbe at least partially separated from stent 2108 containing the valve. Insome embodiments, at least the additional stent or portion thereofpositioned closer to the tip of the delivery system (e.g., stent 2112)may be recapturable by the delivery system. To facilitate suchrecapturing, the additional stent may be formed in a pyramid or wingcross-sectional configuration 2118 (FIG. 21E). In some embodiments, thewing(s) or spikes of stent 2112 (and/or 2114) may be formed at variouspositions/heights along a central axis of stent 2108 similar to, forexample, the stent shown in FIG. 7B. Having different positions/heightsfor at least some of the wings or spikes may facilitate engagement with,for example, native valves of different sizes. In some embodiments, thestents shown in FIGS. 21B-21E (e.g., stent 2108) may include at leastone attachment element for removably attaching to a delivery device,similar to attachment elements 808 shown in FIG. 8B.

FIGS. 22A-26C show examples of delivery systems for deliveringstent-valves (e.g., single-stent-valves or double-stent-valves) to animplantation site in accordance with some embodiments of the presentinvention. In some embodiments, the present invention provides aminimally-invasive surgical approach whereby the surgery is performed ona beating heart without the need for an open-chest cavity and heart-lungbypass. The heart may be penetrated, for example, trans-apically througha relatively small opening in the patient's body. For example, toreplace a failed aortic valve, the patient's body may be penetratedthrough an intercostal space (e.g., fifth intercostal space), which is aregion between two ribs. From this access point, the left ventricle maybe penetrated at the apex of the heart. In one approach, a suitablestent-valve delivery system may initially penetrate the body/heart(e.g., delivery system 2600 (FIGS. 25A-26C) which includes an integratedintroducer). In another approach, a separate introducer sheath may beused. A guide wire (hollow needle, catheter, stiff guide wire, etc.) maybe inserted through the introducer to guide delivery of, for example,stent component(s), a valve component, and/or other devices (e.g., anoccluder device). In some embodiments, transluminal, transatrial, ortransventricular access approaches may be used for, for example,tricuspid and/or mitral valve replacement. The right ventricle of theheart may also be accessed for pulmonary valve replacement. This is incontrast to other surgical approaches that deliver replacement valvesvia open-chest cavities. Moreover, as described in greater detail belowin connection with FIGS. 22A-28C, delivery systems according to someembodiments of the present invention release the proximal portion of thestent-valve first, which may allow for testing of the valve when thebody is accessed, for example, trans-parietally. Upon a successful test,the distal portion of the stent-valve may be released. This contrastswith stent delivery systems that initially release the distal portionsof their associated stents.

FIGS. 22A-22D show a delivery system 2200 that includes twoconcentrically-arranged parts, a first assembly (including elements2202-2210) and a second assembly (including elements 2216-2230). Moreparticularly, the first assembly may include tip 2202 at the distal endof the delivery system (with a guide wire passing through the length ofthe delivery system and out the tip), inner shaft 2204, outer sheath2206, metal shaft 2208, and push handle 2210. The second assembly mayinclude outer shaft (distal) 2216, tapered outer shaft connector 2218,outer shaft (proximal) 2220, stent holder 2222, kink protector 2224,hold handle connector 2226, hold handle cup 2228, and O-ring 2230. Asshown, push handle 2210 is located at the proximal end of the deliverysystem. In FIGS. 22A and 22B, outer shaft 2220 has been split along itslength to allow the components of delivery system 2200 to be shown ingreater detail. Valve 2212 and stent(s) 2214 form a third assembly thatcan be, for example, loaded and crimped between the first and secondassemblies.

With respect to the first assembly, inner shaft 2204 functions as alumen for a guide wire. Tip 2202 is bonded at its distal end. As usedherein, bonding refers to any suitable securing/fastening mechanism suchas, for example, adhesive bonding using cyanoacrylate or UV-curingadhesives or thermal bonding/welding using heat energy to melt thecomponents to be assembled. Outer sheath 2206 may be bonded to theproximal section of tip 2202 and may constrain the stent-valve (2212,2214). Outer sheath 2206 may be perforated to allow device flushing viahold handle 2210. The proximal part of the first assembly may bereinforced with metal shaft 2208 and may end into the push handle with aluer connector for guide wire lumen flushing.

With respect to the second assembly, stent holder 2222 may be bondeddistally on distal outer shaft 2216. FIG. 22D shows a perspective viewbetter illustrating the arrangement between the stent-valve (2212, 2214)and stent holder 2222. Distal outer shaft 2216 may be bonded proximallyto proximal outer shaft 2220 via tapered connector 2218. Proximal outershaft 2220 may be bonded via kink protector 2224 to the hold handleassembly, which may include hold handle connector 2226 and hold handlecup 2228. The hold handle assembly may compress O-ring 2230 for sealingdelivery system 2200. A luer connector may allow for device flushing.The flush mechanism may be used to remove trapped air from the deliverysystem prior to its insertion into the body. Alternatively oradditionally, the flush mechanism may be used to cool down a stent(e.g., nitinol stent) prior to its release and/or recapture by flushingthe stent with a cold saline solution. Cooling down the stent may causea reversible modification of its structure, thus reducing itsYoung-modulus and therefore the stent radial force and the forcesnecessary for its delivery and recapture.

Delivery system 2200 is said to be in an open position (FIG. 22C) when(for example) push handle 2210 contacts the hold handle cup 2228. In theopen position, the stent-valve (2212, 2214) may detach from stent holder2222 and fully expand at an implantation site. Prior to delivery system2200 reaching the open position, the stent-valve may be crimped ontodelivery system 2200 by means of a crimping machine (for example) andheld in place by stent holder 2222. Stent holder 2222 may affix to theattachment elements of the stents shown in FIGS. 8A-16. The crimpedstent-valve may be maintained in a collapsed configuration by pullingback the first assembly thus covering the attachment components/stentholder 2222 with outer sheath 2206. Once the outer sheath 2206 isremoved such that it no longer constrains the attachment components, thestent-valve may automatically detach from stent holder 2222 due to theself-expanding property of the stent-valve. Delivery system 2200 is saidto be in a closed position (FIGS. 22A and 22B) when outer sheath 2206fully encompasses the stent-valve (2212, 2214) such that no expansion ofthe stent-valve occurs.

Delivery system 2200 is said to be in a partially open position when(for example) push handle 2210 is partially pushed towards hold handlecup 2228. In this partially open position, the stent-valve (2212, 2214)is deployed proximally and still attached distally to stent holder 2222via the attachment elements. This allows for an accurateimplantation/positioning of the stent-valve. For example, thestent-valve may be partially released proximal to the intendedimplantation site and slightly pushed distally until resistance is felt.Final release of the stent-valve (2212, 2214) may occur by completelypushing the push handle towards hold handle cup 2228 so that deliverysystem 2200 reaches the open position. Such a partially-open position isillustrated in FIG. 27B. In some embodiments, an imaging mechanism maybe used to determine whether the stent-valve is positioned correctly atthe implantation site. For example, roadmapping under fluoroscopy can berealized with angiography, intra-vascular ultrasound (IVUS),intra-cardiac echocardiography (ICE), trans-esophageal echocardiography(TEE) or other mechanism(s) or combination thereof, which imagingmechanism may be at least partially integral to or separate from thedelivery system.

Upon implantation of the stent-valve (2212, 2214), delivery system 2200may revert to the closed position prior to retrieval from the patient'sbody, for example, by holding the first assembly and pushing the secondassembly distally towards tip 2202/outer sheath 2206. In otherembodiments, the handle for releasing the stent-valve may comprise ascrew mechanism for transferring a rotational movement of the handleinto a translational movement of the outer sheath. This type of releasesystem may allow for stepwise, more accurate stent release andrecapturing as well as a reduction of the release force felt by thesurgeon.

FIGS. 23A-23D show another example of a delivery system 2300 inaccordance with an embodiment of the present invention. Delivery system2300 may be substantially similar to delivery system 2200 (FIG. 22)(e.g., closed position, FIGS. 23A and 23B; opened position, FIG. 23C),except delivery system 2300 may additionally include one or more foldedballoons 2302 (e.g., proximal to the stent-valve). Unless otherwiseindicated, like features in FIGS. 23A-23D correspond to the samereference numerals in FIGS. 22A-22D, although the reference numeralshave not been reproduced in FIGS. 23A-23D to avoid overcomplicating thedrawings. The same applies to the stent delivery systems shown in FIGS.24A-24D, FIGS. 25A-C, and FIGS. 27A-C. Balloon 2302 may beinflated/deflated via an additional lumen in proximal outer shaft 2304,for example, to anchor the stent-valve (e.g., a non-self-expandingstent-valve) in place at an implantation site. FIG. 23D shows a crosssection “A-A” of the lumen structure shown in FIG. 23C. The lumenstructure includes 5-lumen tubing 2306 and inner shaft 2308. In otherembodiments, other structures for lumen tubing 2306 may be used (e.g.,bi-lumen tubing where the second lumen is used for balloon inflation anddeflation). Delivery system 2300 may also include access mechanism 2310for balloon inflation/deflation, which may allow connection of a syringeor inflation device to inflate/deflate a balloon. Alternatively oradditionally, tubing with an attached stop-cock may be connected toaccess mechanism 2310.

FIGS. 24A-24D show another example of a delivery system 2400 inaccordance with an embodiment of the present invention. In deliverysystem 2400, proximal outer shaft 2402 may have an increased diameter incomparison to the diameter of proximal outer shaft 2220 (FIG. 22). Theincreased diameter may reduce bleeding when the delivery system is usedwithout an introducer. Alternatively, when an introducer is used, theincreased diameter may match the internal diameter of the introducerwhich, in turn, may depend on the outer diameter of the outer sheath.Having no gap between the introducer and delivery system may reduce therisk of a potential retrieval issue of the delivery system through theintroducer due to entrapped blood. Accordingly, delivery system 2400 mayinclude a floating tube 2404 that fills the gap between the inner andouter assemblies, thus reducing the risk of the inner assembly kinkingunder compression which would result in higher friction forces withinthe delivery system during stent recapturing. Delivery system 2400 maybe substantially similar to delivery system 2200 in all other respects(e.g., closed position, FIGS. 24A and 24B; opened position, FIG. 24C).

FIGS. 25A-C show another example of a delivery system 2500 in accordancewith an embodiment of the present invention. Delivery system 2500 mayinclude one or more balloons 2536 distal to the stent-valve. Having theballoon(s) distal to the stent-valve avoids having to introduce thedelivery system deeper into the body (e.g., into the ascending aorta) inorder to perform dilation, thereby reducing risk of injury to the bodyand improving device handling (e.g., no bending of rigid device over theaortic arch). Balloon(s) 2536 can be used for, for example,valvuloplasty prior to stent-valve implantation and/or post-dilation ofthe implanted stent-valve to improve the anchoring of the stent. FIGS.25B and 25C show the balloon(s) 2536 in closed and open positions,respectively.

The first assembly of delivery system 2500 may include tip 2502, innerballoon shaft 2504, outer sheath 2506, and floating tube 2208. Thesecond assembly may include inner shaft (distal) 2510, stent holdertransition 2512, stent holder 2514, sleeve 2516, tapered transitionshaft connector 2518, and outer shaft (proximal) 2520. The handleassembly may include hold handle connector 2522, hold handle cup 2524,O-ring 2526, metal shaft 2528, and push handle 2530. The balloonassembly may include outer shaft 2532, inner shaft 2534, balloon 2536,and Y connector 2538.

FIGS. 26A-C show another example of a delivery system 2600 in accordancewith an embodiment of the present invention. Delivery system 2600 mayinclude an integrated introducer 2602, which may be an additionalassembly that houses the second assembly. The outer sheath of thedelivery system is shown as 2604. Introducer 2602 may include aconnecting line 2606, a stopcock 2608 and a housing 2610 for the sealingmembrane 2612. Stopcock 2608 may serve as an access point for, forexample, a syringe containing fluid (e.g., saline). Connecting line 2606may serve to transport the fluid from the syringe to the inner lumen ofthe introducer, and sealing membrane 2612 may seal the introducer fromthe outside environment. Upon stent-valve implantation, the componentsof delivery system 2600 (e.g., first assembly and second assembly) otherthan introducer 2602 may be retrieved through the introducer. Then,another medical device such as, for example, a closure device may beintroduced through introducer 2602. Examples of closure devices aredescribed below in connection with FIGS. 29A-33B. As another example,intravascular ultrasound (IVUS) equipment (e.g., mini-probe) may beintroduced through introducer 2602. Delivery system 2600 may besubstantially similar to delivery system 2200 in all other respects.

FIG. 27 is a flowchart 2700 of illustrative stages involved in replacinga failed (e.g., native or artificial) valve in accordance with someembodiments of the present invention. FIGS. 28A-28C illustrate (withoutlimitation) various stages referenced in the flowchart of FIG. 27. Atstage 2702, a stent-valve (e.g., single-stent-valve ordouble-stent-valve) may be removably attached to a delivery system. Forexample, one or more attachment elements of a stent component (e.g.,attachment elements 808, FIG. 8B) may be affixed to a stent holder ofthe delivery device (e.g., stent holder 2222, FIG. 22). A collapsingelement (e.g., outer sheath 2206, FIG. 22) may be placed over theattachment elements/stent holder to maintain the stent-valve in acollapsed configuration and attached to the delivery system.

At stage 2704, the stent-valve may be delivered to an implantation sitein a collapsed configuration. For example, FIG. 28A (“introduction” and“positioning”) shows that stent-valve 2802, while still attached to thedelivery system via stent holder 2804 and fully contained within outersheath 2806, may be introduced to a patient's body along guide wire 2808so that tip 2810 of the delivery system passes through failed valve2812. The delivery system may be manipulated forwards and/or backwards,for example, until the stent-valve is believed to be positionedcorrectly.

At stage 2706, the stent-valve may be partially expanded, for example,to determine (stage 2708) whether the stent-valve is in fact positionedcorrectly and/or to test (stage 2710) whether the stent-valve isfunctioning properly. For example, FIG. 28A (“partial release”) showsthat outer sheath 2806 may be partially removed from proximal section2814 of the stent-valve, while attachment elements 2816 of thestent-valve are still constrained by outer sheath 2806 onto stent holder2804.

At stage 2712, when the stent-valve is positioned correctly at theimplantation site and/or the stent-valve is functioning properly, thestent-valve may be detached from the delivery system in order to causethe stent-valve to expand to its fully-expanded configuration. Forexample, FIG. 28C (“final release”) shows that, upon removal ofattachment elements 2816 and stent holder 2804 from within outer sheath2806, attachment elements 2816 of stent-valve 2802 may detach from stentholder 2804 automatically (or in response to balloon inflation in otherembodiments) thereby causing the stent-valve to expand to itsfully-expanded configuration. The second assembly of the delivery devicemay then be reunited with the first assembly/outer sheath and removedfrom the patient's body. For example, FIG. 28C (“delivery deviceretrieval”) shows that the second assembly 2818 may be passed throughreplacement stent-valve 2802 towards the distal end of the stent-valve.Then, the reunited second assembly 2818 and first assembly/outer sheath2806 may be passed through stent-valve 2802 again in the proximaldirection before exiting the patient's body.

When the stent-valve is not positioned correctly (stage 2708), at stage2714 the stent-valve may be reverted to the collapsed configuration andrepositioned within the patient's body. An illustration of this scenariois illustrated in FIG. 28B (“stent recapturing/repositioning”), in whichouter sheath 2806 is slid in the proximal direction over proximalsection 2814 of the stent-valve in order to recapture the stent-valve.The stent-valve is then repositioned and released such that fixationelement 2820 of the stent-valve receives an annulus 2822 of the failedvalve. Similarly, when the stent-valve malfunctions in response to atest (stage 2710), at stage 2716 the stent-valve may be reverted to thecollapsed configuration and removed from the patient's body.

FIGS. 29A-33B show illustrative embodiments of guide wire compatibleclosure (occluder) devices for sealing access orifices and associatedsurgical instruments in accordance with some embodiments of the presentinvention. Such an occluder may repair, for example, a cardiac accessorifice (e.g., ventricular orifice) used for valve replacement. Theoccluder may be introduced to a patient's body after a replacement valvehas been implanted (or removed due to malfunction or complication duringinstallation). Embodiments of the present invention address shortcomingswith conventional closure devices, such as the looseness of their fit.Conventional closure devices also lack a central lumen, which rendersthem incompatible with guide wire delivery systems.

FIGS. 29A and 29B are side and perspective views of an occluder 2900 inaccordance with some embodiments of the present invention. Occluder 2900may include stainless steel wire, nitinol, textile fibers, fills,biocompatible materials, and/or other suitable materials which allow thedevice to perform as intended. In some embodiments, at least a portionof occluder 2900 may be fitted/filled with a flexible but tight materialsuch as, for example, a membrane or foam. Occluder 2900 may or may notinclude a skeleton (e.g., lattice structure with a filling material)and/or sealing membranes. Such a skeleton may comprise nitinol,stainless steel, magnesium, nylon, polyester, polypropylene,polydioxanon, other suitable material(s), or a combination thereof. Thefilling material may include, for example, polyester, polyurethane,gelatine, other suitable material(s), or a combination thereof. Whenoccluder 2900 includes a sealing mechanism, such a mechanism may beflexible such that it does not interfere with the expanding orcollapsing of occluder 2900 (described below) according to someembodiments of the present invention.

Top portion 2902 of occluder 2900 may be positioned on the luminal sideof an access orifice, while bottom portion 2904 may be positionedoutside the access orifice. Guide wire compatibility may be achievedthrough a central channel within occluder 2900. The central channel mayinclude at its bottom end, for example, a hollow screw device 2906 forattaching occluder 2900 to a catheter during delivery and detaching theoccluder from the catheter upon installation within the access orifice.In other embodiments, occluder 2900 may be attached/detached to acatheter by a thin wall that can be twisted off, by a connectionmechanism in the shape of a hook, or by a mechanism that detaches viagalvanic corrosion or the like.

Occluder 2900 may include a channel sealing mechanism 2908 such as, forexample, a self-sealing membrane and/or foam. In some embodiments,channel sealing mechanism 2908 may include a valve (e.g., one or moreplastic leaflets). Channel sealing mechanism 2908 may prevent blood-flowthrough the occluder from top/luminal portion 2902 to bottom portion2904 after the occluder is installed within the access orifice. Duringdelivery, the positioning of a guide wire through channel sealingmechanism 2908 (and the central channel) may or may not substantially orentirely prevent blood-flow through channel sealing mechanism 2908. Insome embodiments, mechanism 2908 may rely, at least in part, on bloodclotting in order to form a seal. In some embodiments, mechanism 2908(including a membrane, an iris mechanism, or collapsible walls) may formthe seal (with or without assistance from blood clotting).

In some embodiments, top/luminal portion 2902 of occluder 2900 may bemade from different material(s) (or the same material(s) but havingdifferent characteristics) than the material(s) used for bottom/outerportion 2904. For example, bottom/outer portion 2904 made be made from acoarser or more porous material than top/luminal portion 2902 tofacilitate the formation of scar tissue on the outer portion.Bioabsorbable material(s) may also be used for portion 2902 and/or 2904of occluder 2900 (e.g., magnesium and/or polydioxanone for a skeletonportion and/or polydioxanone, polyhydroxybutyrate, and/or gelatin as afiller).

FIG. 30 shows a perspective view of a guide wire 3000 for guiding thedelivery of occluder 2900 to the access orifice. Guide wire 3000 may bethe same guide wire used, for example, for a valve replacement surgeryinvolving one of the delivery systems shown in FIGS. 22A-26C. FIG. 31shows a perspective view of a threaded catheter 3100 for attaching tooccluder 2900 during delivery and detaching from occluder 2900 onceinstallation of the occluder is complete. As shown in FIGS. 32A and 32B,screw device 2906 of occluder 2900 may attach to threaded catheter 3100,and occluder 2900 may be loaded into second catheter 3202. For example,second catheter 3202 may be part of the delivery system (e.g., FIG.26A-C) used for delivery of a replacement valve. Guide wire 3000 mayextend through both the central channel of occluder 2900 and secondcatheter 3200. Guide wire 3000 may also be removable and reinsertable.FIG. 32B shows that the occluder can be partially unloaded by movingcatheter 3100 relative to catheter 3202. Advantageously, if occluder2900 is not positioned correctly upon partial release, it can bereloaded into catheter 3202 and relocated to the proper location withinthe access orifice without excessive manipulation of occluder 2900and/or the associated delivery instruments.

FIGS. 33A and 33B illustrate side and perspective views of occluder 2900in an expanded configuration within an access orifice in accordance withan embodiment of the present invention. Preferably, luminal/top portion2902 and outer/bottom portion 2904 of occluder 2900 cover the accessorifice completely. The central channel is also preferably sealed by,for example, a self-sealing membrane and/or sealing foam 2908.

Thus it is seen that stent-valves (e.g., single-stent-valves anddouble-stent-valves) and associated methods and systems for surgery areprovided. Although particular embodiments have been disclosed herein indetail, this has been done by way of example for purposes ofillustration only, and is not intended to be limiting with respect tothe scope of the appended claims, which follow. In particular, it iscontemplated by the inventors that various substitutions, alterations,and modifications may be made without departing from the spirit andscope of the invention as defined by the claims. Other aspects,advantages, and modifications are considered to be within the scope ofthe following claims. The claims presented are representative of theinventions disclosed herein. Other, unclaimed inventions are alsocontemplated. The inventors reserve the right to pursue such inventionsin later claims.

We claim:
 1. A replacement valve for use within a human body comprising:a valve component; and a stent component comprising: a first sectioncomprising an annular groove, and a second section for housing the valvecomponent, wherein: the stent component and the valve component areconfigured to form a stent-valve, the stent-valve is configured: in acollapsed configuration for delivery at an implantation site, aself-expanding expanded configuration after delivery to the implantationsite; the annular groove is defined by an annular indentation of thestent component which correspondingly presents an indented interiorsurface of the stent component, the annular groove including a diameterthat is slightly larger than a diameter of the implantation site suchthat the stent-valve is secured in place by a friction fitting; thevalve component is housed by the second section and extends down to theannular groove of the first section, the valve component is axiallytaller than the annular groove.
 2. The replacement valve according toclaim 1, wherein the stent component further comprises a plurality ofattachment elements for removable attachment to a complimentarystructure of a delivery device for delivering the replacement valve, theattachment elements positioned at an opposite end of the stent componentto the first section.
 3. The replacement valve according to claim 2,wherein there are three attachment elements.
 4. The replacement valveaccording to claim 2, wherein when the stent-valve is in the expandedconfiguration, the diameter of the stent component in a region of theattachment elements is smaller than the diameter of the second sectionof the stent component.
 5. The replacement valve according to claim 2,wherein the attachment elements project partially inwardly toward acenter axis of the stent component.
 6. The replacement valve accordingto claim 2, wherein each attachment element comprises a geometricalopening.
 7. The replacement valve according to claim 1, wherein thestent component comprises a structure including a plurality of cells. 8.The replacement valve according to claim 7, wherein the plurality ofcells comprise closed cells to facilitate recapture of the stent-valvefrom a partially expanded condition to the collapsed configuration. 9.The replacement valve according to claim 1, wherein the valve componentcomprises a valve made from bovine pericardium.